Means for controlling electric motors.



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MEANS FOR CONTROLLING ELECTRIC I OTORS.

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UNITED STATES PATENT OF ICE,

MONTGOMERY WADDELL, OF NEW YORK, N. Y., ASSIGNOR, BY DIRECT AND MESNE ASSIGNMENTS, TO THE GENERAL ELECTRIC COMPANY, OF NEW YORK.

MEANS FOR CONTROLLING ELECTRIC MOTORS.

SPECIFICATION forming part of Letters Patent No. 666,121, dated January 15, 1901.

Application filed March 23, 1887. Renewed January 18, 1897. Serial No. 619,677- (No model.)

I a whOm/ it y 007106772: large one is running on full potential, where- Be it known that I, MONTGOMERY WAD- upon the small motor may be cut out of the DELL, a British subject, residing at New York, circuit. in thecounty of New York and State of New By means of my proposed arrangement I 5 York, have invented certain new and useful am also enabled to stop the large motor with- Improvements in Means for Controlling Elecout the application of brakes thereto, the in- 5 trio Motors; and I do hereby declare the folterruption of the motion being effected either lowing to be a full, clear, and exact descripgradually or instantly, as desired.

tion of the invention, such as will enable oth- In the accompanying drawing, illustrative 1o ers skilled in the art to which it appertains to of my invention, I have shown the same as make and use thesame. applied to an ordinary type of motor A, pro- My invention relates to certain new and usevided with the field-coils L and armature C. ful improvements in means for controlling B indicate the terminals of a dynamo-electric electric motors, the disposition of parts chosen machine or its equivalent of any convenient 15 being such that the motor when loaded may construction,and interposed in series between be readily actuated from the electrical source the dynamo-electric machine B and the motor of power, or when in operation may be in- A is a small motor G, provided with a cutstantly or gradually stopped or its speed of out switch D and the brake E, operated by rotation diminished without the application the brake-lever F.

20 of mechanical braking devices. In starting up the motor Athe small motor It is well known that an electric motor G is introduced in series by means of the when loaded cannot readily be operated from switch D. It immediately attains its full the actuating-dynamo to run on constant pospeed and total electromotive force from the tential owing to the motor forming a dead source of power. The brake-leverFis there- 2 short circuit until it obtains its speed and upon applied, reducing the speed of motor G,

maintains an equal potential to that of the thereby causing its counter electromotive feeding-conductors. To obviate this diififorce to drop and permitting a current to flow culty, it has heretofore been customary to through it and through the large motor A. interpose resistances in series with the electric The application of the brake is continued and 0 source of power and the motor and then graduthe speed of the small motor further diminally reduce the resistances to nothing, by ished until a sufficient current passes through which time the motor would have received its the large motor A to start it in operation. full speed and would have acquired the same The speed of the small motor being still furpotential as that of the conductors. ther decreased, the speed of the large one will 5 The purpose of my invention is to substiincrease proportionately, and the potential tute in series for the resistances referred to of the same will rise in proportion as that of a second motor of smaller size, which motor G drops until when G is brought to a full having a comparatively inappreciable load to stop the large motor A is running on full pocarry will at once attain its full speed and tential. Thesmall motor Gmay then be cut 40 full potential. The speed of the small motor out of circuit by throwing the switch into the is then diminished by mechanical means or position shown in the dotted lines in the 0 otherwise, thereby lowering its counter elecdrawing. tromotive force and permitting a current to It is evident that the switch and the means flow through it and through the large motor, for controlling the speed of the small motor 5 the latter beginning to operate when this our- G may constitute one and the same device,

rent reaches a certain point. The speed of so as to be operated bya single manipulation. the small motor being still turther decreased, The motors may be shunt-Wound or may be the potential of the large one will increase wound in series, according to the purpose for until, when the small motor is stopped, the which they are to be employed. It is preferable, however, to have shunt-fields for the small motor G, as they can then be on before the main switch is closed.

YVhile I have shown the secondary motor as entirely independent of mechanical connection with the primary motor, it is evident that the two may be built in together upon the same frame and framework without departing from the spirit of my invention.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is-

1. A controlling device for electric motors, consisting of a secondary motor in series therewith and means for lessening the speed of said secondary motor, substantially as described.

2. A controlling device for an electric motor, consisting of a secondary motor whose armature is in series with the armature of the motor to be regulated, and means for lessening the counter electromotive force of said secondary motor, substantially as described.

3. A controlling device for an electric motor consisting of a secondary motor whose armature is in series with the armature of the motor to be regulated, means for lessening the counter electromotive force of said secondary motor, and a cut-out switch for the secondary motor, substantially as described.

t. The combination with an electric motor of a counter-electromotive-force regulator consisting of a second dynamoelectric ma chine whose armature is in series with the armature of the motor to be regulated, and independent means for varying the counter electromotive force of the said second dynamo-electric machine, substantially as described.

5. The combination with an electric motor, of a controlling device therefor consisting of a secondary motor having a comparatively inappreciable load, the field-magnets of the two motors being connected up in series; substantially as described.

6. The combination with an electric motor, of a controlling device therefor consisting of a secondary motor having a comparatively inappreciable load, the field-magnets of the two motors being connected up in series, and means for lessening the speed of said secondary motor; substantially as described.

7. The combination with an electric motor, of a controlling device therefor consisting of a secondary motor having a comparatively inappreciable load, the field-magnets of the two motors being connected up in series, and a cut-out switch for the secondary motor; substantially as described.

8. A controlling device for electric motors, consisting of a secondary motor in series therewith, the coils of said secondary motor being shunt-wound, a cut-out switch, and means for lessening the cou nt-er electromotive force of the secondary motor, substantially as described.

9. A controlling device for electric motors, consisting of a secondary motor in series therewith, means for lessening the speed of rotation of said secondary motor and a cutout switch for said secondary motor, substantially as described.

10. The combination of an electric motor, and a secondary regulating-motor in series therewith, the said secondary motor having its coils shunt-wound, and a cut-out switch and means for lessening the speed of rotation of the secondary motor, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

MONTGOMERY WADDELL.

Witnesses:

ARCHER C. S'rrrEs, O. WELLMAN PARKS. 

